Agree with you there generally. Like I said I don't expect people to agree with my view, but the question was asked so I thought I'd share an alternative perspective. Essentially, I think almost everyone has travelled unnecessarily during the pandemic, and the distinction between going across the city and going across the continent is relatively small. It's worse, but if it's compensated by "safer" behaviour on the other side, it is a defensible choice. Taking unnecessary risks that contribute to spreading the virus to another part of the city is generally accepted, even though that's the main driver of community spread. It's not the odd house party, crowded pubs, busy restaurants, it's just meeting friends and family even in controlled circumstances.
Most people in this thread said the person they knew got covid despite being very conscientious, very safe, because it's those inconsequential moments that build up to allow the spread to happen. I chose to drop out of that. But rather than become a hermit - which I think is the morally righteous thing to do, but a very dangerous choice to make personally - I chose to take different risks, with the broad goal of creating the best conditions to live healthily and safely for a sustainable period. This new strain raises extra questions but the reality is this new strain could only spread from the South East to every other part of the UK because people were involved in unnecessary travel, and drawing a distinction between this piece of land or that one seems a little contrived.
So I think the people who have chosen to live like a hermit can afford themselves the moral superiority to say "this is the way to live", but for people who have decided that some level of "unnecessary risks" is justifiable, it seems a little disingenuous to point the finger at this one choice. And it is worth clarifying that I didn't go on holiday, as per the normal description. I was working from another country. I was originally working in London but the office closed, and there was no point paying London rent to work from a smaller London apartment, so I went to work somewhere else where I was less likely to run into an infected person on the street, less likely to spend time indoors during the winter, and less likely to see friends and family. It may have been the wrong choice but it wasn't a frivolous one, as per the usual characterisation. Whether those nuances matter are up to you really.